title: Beam profile disturbances from implantable pacemakers or implantable cardioverter-defibrillator interactions.
abstract: The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of a medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.
authors.affiliation: Tri-State Regional Cancer Center, Medical Physics Section, Ashland, Kentucky 41101, USA. mgossman@tsrcc.com
authors.forename: Michael S
authors.initials: MS
authors.lastname: Gossman
authors.forename: Bipinpreet
authors.initials: B
authors.lastname: Nagra
authors.forename: Alison
authors.initials: A
authors.lastname: Graves-Calhoun
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Wilkinson
mesh_terms: D017147:Defibrillators, Implantable; D006801:Humans; D009369:Neoplasms / Q000532:radiotherapy*; D010138:Pacemaker, Artificial; D019047:Phantoms, Imaging; D011474:Prosthesis Design; D011874:Radiometry / Q000379:methods; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage